You can lock the Nest thermostat in the settings menu on the thermostat or in the Nest app. Locking ensures that guests or, for example, young children cannot change the settings of the thermostat. You and your family members can still adjust the temperature within the set range.
Important: If you can no longer unlock the Nest thermostat or if the connection to the Heat Link is broken, switch on the heating by pressing the Nest button on the Heat Link. Also do not forget to press the button if the heating is to be switched off.
For the detailed steps for unlocking or locking the thermostat via the app or thermostat itself, we recommend that you read the steps in this Google Nest article.